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vhost: replace SMP with thread fence for control path

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Simply replace the smp barriers with atomic thread fence for vhost control
path, if there are no synchronization points.

Signed-off-by: Joyce Kong <joyce.kong@arm.com>
Reviewed-by: Ruifeng Wang <ruifeng.wang@arm.com>
Reviewed-by: Maxime Coquelin <maxime.coquelin@redhat.com>
This commit is contained in:
Joyce Kong 2020-12-21 23:50:33 +08:00 committed by Ferruh Yigit
parent 5faf0a9c54
commit a33c3584f3
4 changed files with 14 additions and 14 deletions
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18
lib/librte_vhost/vhost.c
View File

@ -106,7 +106,7 @@ __vhost_log_write(struct virtio_net *dev, uint64_t addr, uint64_t len)
return;
/* To make sure guest memory updates are committed before logging */
rte_smp_wmb();
rte_atomic_thread_fence(__ATOMIC_RELEASE);
page = addr / VHOST_LOG_PAGE;
while (page * VHOST_LOG_PAGE < addr + len) {
@ -144,7 +144,7 @@ __vhost_log_cache_sync(struct virtio_net *dev, struct vhost_virtqueue *vq)
if (unlikely(!dev->log_base))
return;
rte_smp_wmb();
rte_atomic_thread_fence(__ATOMIC_RELEASE);
log_base = (unsigned long *)(uintptr_t)dev->log_base;
@ -163,7 +163,7 @@ __vhost_log_cache_sync(struct virtio_net *dev, struct vhost_virtqueue *vq)
#endif
}
rte_smp_wmb();
rte_atomic_thread_fence(__ATOMIC_RELEASE);
vq->log_cache_nb_elem = 0;
}
@ -190,7 +190,7 @@ vhost_log_cache_page(struct virtio_net *dev, struct vhost_virtqueue *vq,
* No more room for a new log cache entry,
* so write the dirty log map directly.
*/
rte_smp_wmb();
rte_atomic_thread_fence(__ATOMIC_RELEASE);
vhost_log_page((uint8_t *)(uintptr_t)dev->log_base, page);
return;
@ -1097,11 +1097,11 @@ rte_vhost_clr_inflight_desc_split(int vid, uint16_t vring_idx,
if (unlikely(idx >= vq->size))
return -1;
rte_smp_mb();
rte_atomic_thread_fence(__ATOMIC_SEQ_CST);
vq->inflight_split->desc[idx].inflight = 0;
rte_smp_mb();
rte_atomic_thread_fence(__ATOMIC_SEQ_CST);
vq->inflight_split->used_idx = last_used_idx;
return 0;
@ -1140,11 +1140,11 @@ rte_vhost_clr_inflight_desc_packed(int vid, uint16_t vring_idx,
if (unlikely(head >= vq->size))
return -1;
rte_smp_mb();
rte_atomic_thread_fence(__ATOMIC_SEQ_CST);
inflight_info->desc[head].inflight = 0;
rte_smp_mb();
rte_atomic_thread_fence(__ATOMIC_SEQ_CST);
inflight_info->old_free_head = inflight_info->free_head;
inflight_info->old_used_idx = inflight_info->used_idx;
@ -1330,7 +1330,7 @@ vhost_enable_notify_packed(struct virtio_net *dev,
vq->avail_wrap_counter << 15;
}
rte_smp_wmb();
rte_atomic_thread_fence(__ATOMIC_RELEASE);
vq->device_event->flags = flags;
return 0;

6
lib/librte_vhost/vhost.h
View File

@ -728,7 +728,7 @@ static __rte_always_inline void
vhost_vring_call_split(struct virtio_net *dev, struct vhost_virtqueue *vq)
{
/* Flush used->idx update before we read avail->flags. */
rte_smp_mb();
rte_atomic_thread_fence(__ATOMIC_SEQ_CST);
/* Don't kick guest if we don't reach index specified by guest. */
if (dev->features & (1ULL << VIRTIO_RING_F_EVENT_IDX)) {
@ -770,7 +770,7 @@ vhost_vring_call_packed(struct virtio_net *dev, struct vhost_virtqueue *vq)
bool signalled_used_valid, kick = false;
/* Flush used desc update. */
rte_smp_mb();
rte_atomic_thread_fence(__ATOMIC_SEQ_CST);
if (!(dev->features & (1ULL << VIRTIO_RING_F_EVENT_IDX))) {
if (vq->driver_event->flags !=
@ -796,7 +796,7 @@ vhost_vring_call_packed(struct virtio_net *dev, struct vhost_virtqueue *vq)
goto kick;
}
rte_smp_rmb();
rte_atomic_thread_fence(__ATOMIC_ACQUIRE);
off_wrap = vq->driver_event->off_wrap;
off = off_wrap & ~(1 << 15);

2
lib/librte_vhost/vhost_user.c
View File

@ -1690,7 +1690,7 @@ vhost_check_queue_inflights_split(struct virtio_net *dev,
if (inflight_split->used_idx != used->idx) {
inflight_split->desc[last_io].inflight = 0;
rte_smp_mb();
rte_atomic_thread_fence(__ATOMIC_SEQ_CST);
inflight_split->used_idx = used->idx;
}

2
lib/librte_vhost/virtio_net.c
View File

@ -1663,7 +1663,7 @@ uint16_t rte_vhost_poll_enqueue_completed(int vid, uint16_t queue_id,
queue_id, 0, count - vq->async_last_pkts_n);
n_pkts_cpl += vq->async_last_pkts_n;
rte_smp_wmb();
rte_atomic_thread_fence(__ATOMIC_RELEASE);
while (likely((n_pkts_put < count) && n_inflight)) {
uint16_t info_idx = (start_idx + n_pkts_put) & (vq_size - 1);